Rotary mold coating machine



y 1969 M. PIERREI. 3,452,713

ROTARY MOLD COATING MACHINE Filed Jan. 10. 1967 AH?) TM. LY

United States Patent ,703 Int. Cl. B05b 7/14, 13/06 U.S. Cl. 118-308 3 Claims ABSTRACT OF THE DISCLOSURE Centrifugal casting machine for casting pipes and having a retractable support for a hollow core forming the inside of the socket of the pipe. A nozzle for projecting powdered product onto the inner wall of the rotatable mould is fixed on the core support.

The present invention relates to the centrifugal casting of iron pipes and like objects in accordance with the de Lavaud method and more particularly to a machine provided with an improved device for applying a layer of ferrosilicon powder or other powdered product on the mould so as to favour the graphitization during the solidification of the iron.

It is known that the use of ferrosilicon avoids the surface hardening of the pipes and results in a grey iron structure. The ferrosilicon can be applied on the shell or mould either by means of a trough whose length corresponds to that of the mould, this trough being turned over inside the mould, or by means of a gun or projecting nozzle.

Usually, the ferrosilicon projecting or atomizing nozzle is mounted at the end of the casting trough near the casting nose of the latter and the product is projected immediately before pouring by moving the mould-carrying carriage relative to the trough in such manner that the mould is covered with ferrosilicon throughout its length. Now, it is not possible to adopt this arrangement for smalldiameter moulds owing to the excessive size of the product projecting nozzle which extends beyond the pouring trough. In this case, it is necessary to employ a trough which is turned over for coating small-diameter moulds. However this is unsuitable for automatic operation and requires more time than the projecting nozzle device.

The object of the invention is to remedy these drawbacks by providing a centrifugal casting machine with a device which projects a powdered product on the wall of the mould before pouring the metal, said device being suitable for all dimensions of moulds and enabling them to be covered during the movement of the carriage towards the pouring trough in the course of a single forward travel.

The invention aims at providing a centrifugal casting machine employing a rotary mould, said machine comprising a retractable support for the pipe socket core and a nozzle for projecting a powder for coating the inner wall of the mould, said nozzle being fixed to said core support inside said core.

Owing to this arrangement, a mould or shell even of small diameter can be equipped with a coating powder projecting device without loss of production time. Consequently, the production rate is accelerated for moulds of small diameter. Moreover, the coating operation can be rendered automatic.

Further features and advantages of the invention will be apparent from the ensuing description with reference to the accompanying drawing.

In the drawing:

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FIG. 1 is a diagrammatic elevational view, partly in section, of a centrifugal casting machine equipped in accordance with the invention, and

FIG. 2 is a detail sectional view, on an enlarged scale, of the atomizing device.

In the illustrated embodiment, the invention relates to a centrifugal casting machine in which the iron fed by a roughly horizontal passage or trough A is poured into a shell or mould 1 having an axis X-X for casting a pipe which has a socket and is composed for example of iron. The mould 1 rotates about its axis and is mounted on a support carriage 2 which undergoes a movement of translation relative to the trough A.

The mould 1 comprises, at the end thereof corresponding to the socket of the pipe to be obtained, a divergent cavity 3 in the form of a bell in which is mounted a hollow sand core N which determines the inner shape of the socket of the pipe.

The core N is carried by a support S which includes a face plate 4 extended by a protective deflecting cone 5 which has the same axis X-X as the core N and mould 1. The plate 4 is fitted into the end of the bell 3 of the mould 1.

The support S is mounted in the known manner on the end of a pivotal arm B which is pivotally mounted on the carriage 2. This arm B is adapted to be swung away from the axis X-X of the mould 1 for receiving the core N to be placed in the mould.

According to the invention, a nozzle 6 for blowing coating powder, for example ferrosilicon is mounted inside the support S of the core N on the axis X-X of the mould 1.

When a core N is placed in position on the support S, the nozzle 6 is surrounded by this core as by a sleeve. It will be observed that the diameter of the inner cavity of the core N permits easily housing the nozzle 6 even if the core N is for a mould of small diameter (for example for casting pipes having a diameter of 50 mm.). The nozzle 6 is for example suspended from an arm 7 fixed inside the deflecting cone 5. This nozzle is fed with ferrosilicon powder by a pipe 8 which is partially flexible so as to allow the pivoting movement of the arm B. The pipe 8 is connected to a ferrosilicon supply tank 9 carried by the carriage 2. Extending into the tank 9 containing the ferrosilicon powder is the perforated end of a pipe 10 for blowing compressed air. The pipe 10 is connected to a compressed air supply pipe 11 through a distributor D controlled by an electrovalve E. The pipe 11 is flexible and suspended from hooks 12 which are movable so as to follow the movements of the carriage.

The device is employed in the following manner:

When the support S has received a core N, the carriage 2 is immediately shifted in the direction of the trough A. At the same time, the distributor D is actuated so as to supply compressed air to the tank 9 and consequently the blow of the ferrosilicon powder through the nozzle 6.

The mould 1 is therefore coated solely during the forward travel of the carriage and consequently with no loss of time. The pipe is cast in the course of the return travel of the carriage.

It will be understood that the electrovalve E actuating the distributor D can be controlled automatically at the same time as the carriage starts to move. Further, as has been explained hereinbefore, the inner cavity of the hollow socket cores enables a projecting nozzle to be disposed therein even when it concerns cores of smalldiameter moulds.

Having now described by invention, what I claim as new and desire to secure by Letters Patent is:

1. In a centrifugal casting machine for casting socketend pipes comprising a rotary mould rotatable in a carriage and having an innefwall and a hollow core fbffdr'fning the inside of the pipe socket end carried by a support retractable from said mould; the feature that a nozzle for projecting a powdered product for coating the inner wall of said rotary mould is combined with said support, said nozzle being mounted on said support to be held in position axially of said mould and located inside said core.

2. A machine as claimed in claim 1, further comprising a tank containing said powdered product and mounted on said carriage and a flexible pipe putting said nozzle in communication with the powdered product in said tank and allowing retraction of said support.

3. A machine as claimed in claim 2, comprising a flexible pipe for connection to a source of compressed air and communicating with the interioroi said tank for blow- 1,963,149 6/1934 Russell et a1. 164-267 2,336,946 12/1943 Marden et al 118-308 X 2,419,951 5/ 1947 Kastel 1l8321 X WALTER A. SCHEEL, Primary Examiner.

JOHN P. MCINTOSH, Assistant Examiner- U5. :1. X.R. 

